Optical systems are used for a wide range of applications, such as spectroscopy, transmission of data modulated on light beams and image projection. Optical systems use various optical elements, including mirrors, prisms, lenses and diffractive structures.
A paper titled: “Total internal reflection diffraction grating in conical mounting”, by L. Eisen et. al., Optical Communications 261, pages 13-18 (2006), the disclosure of which is incorporated herein by reference in its entirety, discusses investigations of surface relief diffraction gratings that involve total internal reflection (TIR) in the substrate on which the gratings are recorded.
US patent application publication 2011/0019258 to Levola describes use of various optical elements in leading illumination light for a liquid crystal on silicon (LCOS) micro-display.
A recently emerging application of optical systems is three dimensional (3D) mapping of objects. Such mapping is used in computer vision, automation and optical image processing.
A paper titled: “Three-dimensional mapping and range measurement by means of projected speckle patterns”, by Garcia et al., published May 26, 2008, in Applied Optics, Vol. 47, No. 16, pages 3032-3040, the disclosure of which is incorporated herein by reference in its entirety, describes various methods used for performing 3D mapping and various light sources which may be used, including sources of both conventional illumination and coherent illumination.
The paper “Projection of speckle patterns for 3D sensing”, by Garcia et el., Journal of Physics, Conference series 139 (2008), the disclosure of which is incorporated herein by reference in its entirety, suggests using a monochromatic parallel beam of laser light.
US patent application publication 2008/0240502 to Freedman et al., the disclosure of which is incorporated herein by reference in its entirety, suggests using a coherent point source with large angular divergence, such as a laser diode, with or without collimation optics.